Old Salt

Nightime infrared images (from THEMIS on the Mars Odyssey spacecraft) show a meandering and branched channel-like form in this region. It is bright (warmer) at night, suggesting exposed bedrock rather than fine-grained materials.

This HiRISE image shows some patches of “pinkish” or “purplish” materials with a distinctive fracture pattern. These patches are very similar in color, morphology, and geologic setting to larger deposits thought to consist of chloride salts, like table salt (NaCl) except that the chlorine anion (Cl-) may be combined with another cation such as magnesium (Mg+) or potassium (K+) rather than sodium (Na+). Such chlorides form when salty water evaporates.

Written by: Alfred McEwen   (29 February 2012)

More info and image formats at http://hirise.lpl.arizona.edu/ESP_025698_1485

Image: NASA/JPL/University of Arizona